1. Field of the Invention
The present invention relates to a vehicle with a high voltage power source mounted thereon, a power source controller for controlling the high voltage power source, a method of starting such a vehicle with the high voltage power source mounted thereon, and a method of utilizing the high voltage power source. More specifically the invention pertains to a technique of handling a power source with a cutoff member that cuts off the output of the high voltage power source in a manual manner on the side closer to the power source.
2. Description of the Related Art
A diversity of apparatuses, such as electric vehicles, with the high voltage power source mounted thereon and special vehicles that carry out various works with the high voltage electric power of the high voltage power source mounted thereon have been used in various fields. A variety of safety devices are installed in such apparatuses and vehicles to ensure the safety of use of the high voltage power source. One of such safety devices is a cutoff member that is handled in a manual manner to cut off the output of the high voltage power source on the side closer to the power source. In electric vehicles and hybrid vehicles that utilize electricity as one of the energy sources, a cutoff member called a service plug is provided to prevent the mechanic, who carries out the maintenance, from unintentionally coming into contact with the high voltage system. The service plug is removed during the work of maintenance. One proposed safety device, which is disclosed in JAPANESE PATENT LAID-OPEN GAZETTE No. 6-98403, independently detects the state of voltage application to the high voltage power source system and the state of charge in the battery, keeps a protection cover over the high voltage system fixed according to the requirements, and permits voltage application to the high voltage system and charging the battery only when the protection cover is kept fixed.
Especially in the vehicles with the high voltage power source, it is required to prohibit the output of the high voltage power source to the high voltage system in the case of dismantling the vehicle or its parts or in the case of cutting the vehicle, for example, after a traffic accident. This keeps the mechanics or rescue corps from the accidental contact with the high voltage system. For such purposes, a variety of safety devices have been proposed. The most effective measure is, however, still a manual operation of the cutoff member like the service plug. In some prior art vehicles with the manually handled cutoff member like the service plug, there is a mechanism of detecting the open state of a protection cover that allows the cutoff member to be attached or detached. One example of such mechanism is an interlock mechanism, which assumes that the driver or the mechanic intends to carry out inspection and maintenance of the vehicle or the apparatus while the protection cover is in the open state and opens the contact of a relay provided in the high voltage system (that is, cuts off the high voltage power source).
Application of the interlock mechanism, however, causes another problem that the start of the vehicle or the apparatus is not allowed even in the case where the driver or the mechanic simply forgets to shut the protection cover. The safety and the convenience naturally conflict with each other. In any systems, the enhanced safety leads to the restricted convenience. If the driver or the mechanic forgets to shut the protection cover, the driver can not start the vehicle. In such cases, it is highly probable that the vehicle has undergone some maintenance. The driver may thus suspect that there should be some failure in maintenance of the vehicle. The protection cover over the service plug is not observable unless the hood of the vehicle is open. This also makes it difficult to find such a simple cause of the failed start as forgetting to shut the protection cover.
The object of the present invention is thus to improve the convenience of use of a vehicle and an apparatus with a high voltage power source mounted thereon without reducing the degree of safety and especially to allow a start of the vehicle and the apparatus when the safety conditions are fulfilled.
At least part of the above and the other related objects is attained by a vehicle with a high voltage power source mounted thereon. The vehicle includes: a relay having a contact interposed between the high voltage power source and a power line of the vehicle; a relay actuation requirement unit that outputs a requirement signal to close the contact of the relay; a cutoff member that is handled in a manual manner to cut off output of the high voltage power source on a side closer to the power source than the relay; an operation detection unit that detects an operation including a specific operation to handle the cutoff member; a prohibition unit that prohibits the contact of the relay from being closed in response to detection of the specific operation to handle the cutoff member; a driving action detection unit that detects a driver""s driving action; an evaluation unit that evaluates a result of the detection of the operation detection unit, based on a result of the detection by the driving action detection unit; and a cancellation unit that, when the evaluation unit specifies that the evaluated result of the detection of the operation detection unit is an operation other than the specific operation to handle the cutoff member, cancels the function of the prohibition unit, which prohibits the contact of the relay from being closed, but actuates the relay in response to the requirement signal output from the relay actuation requirement signal.
The technique of the present invention is also actualized by the corresponding method of starting such a vehicle with the high voltage power source mounted thereon. The present invention is accordingly directed to a method of starting a vehicle with a high voltage power source mounted thereon. The method includes the steps of: interposing a contact of a relay between the high voltage power source and a power line of the vehicle; detecting a preliminary operation to handle a cutoff member that cuts off output of the high voltage power source in a manual manner on a side closer to the power source than the relay; prohibiting the contact of the relay from being closed in response to detection of the preliminary operation to handle the cutoff member; detecting a driver""s driving action; evaluating the detected preliminary operation, based on a result of the detection of the driving action; and when the evaluation specifies that the detected preliminary operation is other than a specific operation to handle the cutoff member, canceling the prohibition on the function of closing the contact of the relay in response to input of a requirement signal to close the contact of the relay, so as to allow a start of the vehicle.
The present invention is also directed to a power source controller disposed in an apparatus with a high voltage power source mounted thereon. The power source controller includes: a relay having a contact interposed between the high voltage power source and a power line of the apparatus; a cutoff member that is handled in a manual manner to cut off output of the high voltage power source on a side closer to the power source than the relay; an operation detection unit that detects an operation including a specific operation to handle the cutoff member; a prohibition unit that prohibits the contact of the relay from being closed in response to detection of the operation; an operational action detection unit that detects an operator""s operational action of the apparatus; an evaluation unit that evaluates a result of the detection of the operation detection unit, based on a result of the detection by the operational action detection unit; and a cancellation unit that, when the evaluation unit specifies that the evaluated result of the detection of the operation detection unit is an operation other than the specific operation to handle the cutoff member, cancels the function of the prohibition unit, which prohibits the contact of the relay from being closed, in response to input of a requirement signal to close the contact of the relay.
The technique of the present invention is further actualized by the corresponding method of utilizing the high voltage power source mounted on the apparatus. The present invention is accordingly directed to a method of utilizing a high voltage power source mounted on an apparatus. The method includes the steps of: interposing a contact of a relay between the high voltage power source and a power line of the apparatus; detecting a preliminary operation to handle a cutoff member that cuts off output of the high voltage power source in a manual manner on a side closer to the power source than the relay; prohibiting the contact of the relay from being closed in response to detection of the preliminary operation to handle the cutoff member; detecting an operator""s operational action of the apparatus; evaluating the detected preliminary operation, based on a result of the detection of the operational action; and when the evaluation specifies that the detected preliminary operation is other than a specific operation to handle the cutoff member, canceling the prohibition on the function of closing the contact of the relay in response to input of a requirement signal to close the contact of the relay, so as to allow a start of the apparatus.
Any of the above applications of the technique of the present invention detects an action performed by the driver of the vehicle or the operator of the apparatus and evaluates a detected operation, based on the detected action. When the evaluation shows that the detected operation is other than a specific operation to handle the cutoff member, regardless of the detected action, the arrangement cancels the prohibition on the function of closing the contact of the relay. This arrangement allows the contact of the relay to be closed and outputs the high voltage power source to the power line of the vehicle or the apparatus, in the case where the driver""s action or the operator""s action intends to close the contact of the relay. This enables the vehicle or the apparatus to start in response to a starting requirement.
In the vehicle of the present invention, the driver""s action may be detected by a sensor that detects an instruction to drive the vehicle. In this structure, the evaluation may specify that the detected operation is other than the specific operation to handle the cutoff member, when the instruction to drive the vehicle is detected at least twice in a preset first time period. It is generally improbable that the consecutively output two or more instructions to drive the vehicle within the preset time period is just some error. In such cases, it is practical to regard the detected operation to handle the cutoff member is a wrong recognition This arrangement enhances the convenience of use of the vehicle or the apparatus, while assuring the sufficient safety of working.
In the above arrangement, the condition of the evaluation may be initialized when a second preset time period has elapsed since a first detection of the instruction to drive the vehicle. For example, when several tens minutes have elapsed between the first detection and the second detection, it is impractical to regard the two instructions as the consecutive, related instructions. The first time period and the second time period may be determined empirically, based on the results of actual operations of a large number of users and the studies on the expected behaviors of the human. It is probable that the driver simply forgets to shut the cover of the service plug and gives a starting instruction through an operation of the ignition key. Various data, for example, the time interval between consecutive key operations to start the vehicle and the elapse of time required for inspection of the vehicle between the first starting action and the second starting action, are statistically processed to determine these preset time periods.
In electric vehicles and hybrid vehicles, the high voltage power source may be a battery or fuel cells used to drive motors. The high voltage power source also includes high voltage batteries used in special vehicles that carry out various works with the high voltage electric power of the battery. The principle of the present invention is applicable to a diversity of apparatuses with a high voltage battery or a capacitor, as well as to the diversity of vehicles.
In any of the above applications of the present invention, when the operations including the specific operation to handle the cutoff member, one preferable arrangement informs the driver of the detection. Such information may be given in the form of visual alarm, for example, light flashing, or sound alarm. The alarm may be given when the operations including the specific operation to handle the cutoff member is detected or when the operations including the specific operation to handle the cutoff member is detected and a requirement to start the vehicle is received.
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment with the accompanying drawings.